RE: Function to accept node and name of subnode in p

Ok that's perfect.  Thanks Ken.


-----Original Message-----
From: G. Ken Holman [mailto:gkholman@xxxxxxxxxxxxxxxxxxxx]
Sent: Wednesday, August 20, 2008 2:40 PM
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re:  Function to accept node and name of subnode in
parameter string

At 2008-08-20 14:29 -0500, Bordeman, Chris wrote:
>Hi all.  I need to create a 2.0 function that will accept an element()?
>and a xs:string.  The string will contain the name of a subnode of the
>first parameter.
>
>The function will do something like this:
>
><!-- Given any node and the name of a subnode, returns
>      the nonempty subnode's value or N/A --> <xsl:function
>name="fn:ValueOrNA" as="xs:string">
>         <xsl:param name="node" as="element()?"/>
>         <xsl:param name="childelementname" as="xs:string"/>
>         <xsl:choose>
>                 <xsl:when test="$node and $node/$childname != ''">
>                         <xsl:value-of select="$node/$childname"/>
>                 </xsl:when>
>                 <xsl:otherwise>
>                         <xsl:value-of select="'N/A'"/>
>                 </xsl:otherwise>
>         </xsl:choose>
></xsl:function>
>
>But it always seems to return just the second string I pass in, not the

>value of the subnode.

Yes, because in XSLT 2.0 any step in a location path is allowed to be a
primary expression of which a string literal is one.

>What's the right way to do this?

By making some assumptions on namespace prefixes and finding the node
you are looking for.

   <xsl:when test="$node and $node/*[name(.)=$childname] != ''">
     <xsl:value-of select="$node/*[name(.)=$childname]"/>
   </xsl:when>

... but the above assumes that your $childname contains the same
prefix-qualified name as your input tree.  If you only want to check on
the name portion without the prefix, then you will need
local-name(.) instead of name(.).

If you need a complete namespace-safe solution then pass in a third
argument:

   <xsl:param name="childns" as="xs:string"/>

... and the following test will work indpendent of any prefix chosen by
the author of the document:

   <xsl:when test="$node and $node/*[local-name(.)=$childname and
                                     namespace-uri(.)=$childns] != ''">
     <xsl:value-of select="$node/*[local-name(.)=$childname and
                                   namespace-uri(.)=$childns]"/>
   </xsl:when>

I hope this helps.

. . . . . . . . . . . . Ken


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